Light signal



W. WELLS LIGHT SIGNAL.

Feb. 4, 19,41.

Filed Marn 29, 1939 f f f INVENTQR Wesze. Wells. BY r h ISHS ATTORNEY Fig. 2;

Patented Feb. 4, 1941 i 2 I' vuNI'rlao STATES PATENT oFFlcE LIGHT SIGNAL Wesley B. Wells, Wilkinsburg, Pa., assig'nor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application March 29, 1939, Serial No. 264,799 2 Claims. (Cl. 177-329) My invention relates to light signals, and parbarrel. The outer lens lil bears around its edges ticularly to light signals of the searchlight type against the bottom of an annular groove I2 which which are capable of selectively projecting a pluis formed in the lens barrel, and is held in place rality of beams of light of different colors from by a ring member I3 and screws I4, a gasket of l .6 a singlelight source. felt or the like preferably being interposed be- 5 More particularly, my present invention relates tween the ring member and the edges of the lens. to light units for searchlight signals of the type The inner lens 9 likewise bears at its edges against described, and has for an object tov improve the the bottom of an annular groove l5 which is adjustable light units described and claimed in formed in the inner end of the lens barrel, and

0 Letters Patent of the United States No. 2,111,650, is held in place by a ring member IS and screws y10 granted to myself and another on March 22, I1, a gasket of felt or the like being interposed 1938, for Light signals. between the ring member andthe edges of the Other objects and characteristic features` of lens. The two lenses are of the well-known my invention will appear as the description proplano-convex type, and are both clear or color- '1,5 ceeds. less. Secured to the outer end of the lens barrel 15 I shall describe one form of light signals emdirectly above the outer lens I0 is a hood I8 which bodying myinvention, and shall then point out performs the usual function of shielding the the novel features thereof in claims. lens I0 from the direct rays of the sun.

In the accompanying drawing, Fig. 1 is a View The light unit A referred to hereinbefore coinpartly in side elevation and partly in vertical prises an elliptical reflector 20 mounted in a metal 20 section, showing one form of light signal emcasing 2 I, and an electric lamp 22, the filament of bodying my invention. Fig. 2 is a fragmentary which is located at one of the conjugate foci of rear elevational View of the signal shown in Fig. the reflector 20. The rear wall of the casing 2| 1, aportion of the door being broken away to is provided with three rearwardly projecting better illustrate the construction of the parts. studs 23 arranged in triangular formation, and-Z5 Fig. 3 is a detail isometric View showing one of mounted on these studs between compressed coil the mounting studs and cooperating parts of the springs 24 which surround the shank portions reflector assembly embodying my invention. of the studs, and nuts 25 which are adjustably Similar reference characters `refer to similar screwed onto the outer end of the studs, is a `3,0 parts in all three views. plate 26. This plate carries a socket 2l which 30 Referring first to Figs. 1 and 2, the light signal projects with some clearance through a hole 28 in the form here shown comprises a box-like casformed in the Teal" Wall 0f the Casing 2i, and ing I provided with a hinged rear door 2 through serves as a support for the previously referred to which convenient access to the interior of the electric lamp 22. Mounted 0n the Studs 23 Outl casing may be had; The door 2 is arranged to be side of the nuts 25 are lock nuts 29 for securing .'35 fastened in its closed position by means of a suitthe nuts 25 in adjuSted positions. It will be apable fastening device 3, and is provided on its `parent that by adjusting the nuts 25 the posirear face with a groove 4 for the reception 0f tion of the lamp filament' With ISSDGC i0 the Iepacking 5, which when the door is closed, engages flector may be varied, and these nuts are so ad- -40 the edge of the casing I and thus seals the casing justed that the filament of the lamp will be lo- 40 against the entrance of dirt or other foreign sub- Gated at the OCH DOUG 0f the TSi-SOCOI, thus e11- stances. `abling the maximum eniciency to be obtained Formed in the forward wall Ia, of the casing from the light unit. I is a large circular opening l through which the Irl a'CCOIdaHCe With my DleSeilt IlVlGiOn, the

light rays from a light unit A which is disposed reflector housing is provided with three radial .45 inside of the casingare adapted to be projected, arms 30, 3I and 32, each of whi-ch is formed with and secured to the forward wall Ia directly in a socket l33. These sockets are adapted to refront of the opening I by means of foulscrews ceive the spherical heads 35 of three studs 35, 36 8 spaced`90 apart is a lens unit L for concentratand 3l which are adjustably screwed into tapped .59 'ing the light rays emitted by the light unit A holes formed in bosses 38, 39 and All) formed at f5() into a signal beam. The lens unit L is of well- `the top and two sides respectively of the casing known construction and comprises adoublet con- I, and the sockets are carefully machined to acsisting of two spaced lenses 9 and I0 mounted in curately fit the heads of the studs for a purpose the inner and outer ends, respectively, of a tubwhich will become apparent hereinafter. Formed #if ular casing II, commonly referred to as a lens in the `opposite sides of these sockets are saw 55 cuts or slots 4I, and extending into each socket through these saw cuts are the opposite sides of a U-shaped spring 42 which is held in place by pins 43. The saw cuts are so located that, when the heads of the studs have fully entered the slots the largest diameters of the heads will have passed the slots, and the sides of the springs are spaced apart distances which are less than the diameters of the heads.

It will be seen, therefore, that in order to insert the head of a stud into any one of the sockets, it will be necessary to force the two sides'of the spring apart, and that when the head of a stud has fully entered a socket, the largest diameter of the head will have'passed the spring, thereby permitting the spring toc'ontract .in a manner to force the head of the stud all of the way into the socket and thus yieldably hold it in place in the socket.

To permit ready adjustment of the ball studs while the reflector assembly is snapped in place, the head 34 of each stud is provided in its outer end with a hexagonal recess 44 for the reception of a wrench or other tool, and a hole 45 is provided in the outer end of each socket through which the tool may be inserted into the recess in the stud. The studs are arranged to be locked in their adjusted position by lock nuts 46 and lock washers 4T provided on the studs. To facilitate snapping the reflector in place onto the studs or removing it from the studs a handle 48 is pro'- vided. l

'Ihe light signal also comprises a suitable operating mechanism S for changing the color of the beam emitted by the signal to provide a plurality of signal-indications. As here shown, this mechanism is similar to that described and claimed in an application for Letters Patent of the United States Serial No. 88,768, vfiled by myself and another on July 3, 1936, for Light signals. Briefly described, this mechanism comprises a top plate 50 of insulating material having secured thereto a polarized electroresponsive means for operating between an intermediate and two extreme positions a spectacle arm I which projects upwardly through a slot in the top plate into an auxiliary casing 52 which is secured to the top plate. The spectacle arm 5I is provided at its upper end with green, yellow and red color screens which align respectively with two windows 53 and 54 of clear glass according as the spectacle arm occupies its one extreme position, its other extreme position or its intermediate extreme position. Only the red screen 55 is shown in the drawing, but spectacle arms of the type described are well-known, and it is therefore deemed to be unnecessary to show this spectacle arm in detail herein.

The mechanism is so positioned with respect to the casingel by suitable means forming no part of my present invention that theA light rays emitted by the light unit A will pass through the windows 53 and 54 of the signal'mechanism and the color screen which happens to be in alignment with these windows in the manner indicated by the dotted lines 56. It will be apparent,

therefore, that the signal will display a green,

red or yellow aspect according as the spectacle arm 5) occupies its one extreme position, its intermediate position or its'other extreme position. I'he top plate 5@ is provided with suitable terminal posts for the reception of plug connectors 51 to enable the signal to be readily connected with external circuits.

In utilizing Athe signal it is contemplated that all light units will be prefocused, that is, adjusted before they leave the factory, so that the conjugate foci will bear a iixed relation to the ball sockets, and it is also contemplated that the studs will be adjusted before the signal leaves the factory so that any unit which is subsequently snapped onto the stud will give maximum signal eciency. In adjusting the studs, a prefo- -cused light unit provided with a precision type lamp bulb is snapped onto the three ball studs and the studs are screwed in or out until the light beam projected by the signal has its maximum intensity. 'Ihe ball studs are turned while mak- .ing this adjustment by inserting a tool through assembly can be readily removed from, and

snapped back onto the ball studs into its original position, thereby making the replacement of lamp bulbs a quick and easy operation. One of the supporting arms on the reflector assemblyv is shorter than the other two, thus making it impossible to install the light unit incorrectly. Since all light units are prefocused, a light unit can be replaced with another and the maximum optical e'iciency of the signal will be maintained.

It will be noted from an inspection of the drawing that in order to remove the operating unit from the casing l, it is necessary to first remove the light unit from the casing. Inasmuch as the light unit can readily be removed from the casing, the time required to replace the operating unit is greatly decreased.

One advantage of a light unit constructed in accordance with my invention is that regardless of the adjustment of the ball studs, all three studs will seat correctly in the associated socket of the light unit without any lost motion, or without any possibility of the light unit not returning to its adjusted position.

Although I have herein shown and described only one form of light signals embodying my -invention, it is understood that various changes and modications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In a light signal the combination with a lens unit fixed in a housing and a light unit having a focal point which is adapted to coincide with the focal point of the lens unit, of means for attaching the light unit to the housing in such a way as' to make the light unit readily detachable and also adjustable, with respect to the lens unit, said -means comprising three screw threaded studs mounted in the housing and arranged in an irregular'triangle including the axis of the signal and having spherical heads to dene the plane of the light unit and each adjustable in the housing in a direction parallel with the axis of the signal to vary the inclination of the plane of the triangle, three sockets integral with the light unit for receiving the spherical heads of the studs and having spherical surfaces cooperating with the heads to allow relative movement of the sockets and the studs to permit inclination of the triangle, and means in each socket for yieldably gripping the spherical heads of said studs when they are in place in said sockets to detachably fasten said light unit to said studs, whereby by adjusting said studs the focal point of the light unit may be made to coincide with the focal point of the lens unit.

2. A light signal comprising a casing having an opening provided with a lens unit, three studs mounted in said housing around said opening and provided With spherical heads and each adjustable in a direction parallel with the axis of said lens unit, a light unit in said casing for supplying light to said lens unit, said light unit being provided with three sockets which are adapted to receive the heads of said studs to position said light unit in said casing, and means in each socket for yieldably gripping the spherical heads of said studs When they are in place in said sockets to detachably fasten said light unit to said studs, each said stud being provided in its outer end with means adapted to receive a tool for adjusting the stud and each said socket being provided with a hole through which access to the associated stud for adjustment purposes may be had when the light unit is in place on the studs.

WESLEY B. WELLS. 

